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Post by 4l04ever on Sept 10, 2016 22:13:01 GMT 1
How do you change them if they get damaged??? You would need to stretch them a long way to get over the crank webs......  ? |
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Post by Tobyjugs on Sept 10, 2016 22:48:36 GMT 1
Cut and glue them together again
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Post by markhoopy on Sept 10, 2016 22:52:27 GMT 1
I would think both suggestions wouldn't work and the only solution would be a crank rebuild.
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Post by 4l04ever on Sept 10, 2016 22:58:30 GMT 1
That is what I was thinking. Maybe better to stick with traditional lab seal and bearings.....
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Post by Tobyjugs on Sept 10, 2016 23:09:22 GMT 1
There are a few good glues around now which work well with rubber seals and are not too hard.
What do you think are the drawbacks about gluing?
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Post by 4l04ever on Sept 10, 2016 23:15:22 GMT 1
I have seen a crank today in a freshly stripped engine after 500 miles, with O-rings and one was damaged, and the middle ones had all swollen up so did not fit properly anymore due to petrol affecting the seal material I presume. If you glue new ones, the glue would need to be petrol/ethanol/oil proof.
Maybe glue new viton O-rings on? Would be tricky to glue while fitted on the bearings/lab seal.
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Post by markhoopy on Sept 10, 2016 23:29:00 GMT 1
The seals are under opposing pressures with each stroke of the piston. Even with a strong, suitable glue it would be difficult to join the seals accurately and if you did manage to do it you would always have that nagging doubt every time you took your bike out for a run.
It would be interesting to hear from a forum member who had tried glueing the labyrinth seals successfully, but I doubt anyone has tried.
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Post by Tobyjugs on Sept 10, 2016 23:30:21 GMT 1
Are the O-rings used as seals?
I thought they were only used for friction to stop the bearings turning in the housings.
It could be a little tricky to glue the O-ring and you might need to sacrifice one or two for practice
Once the O-ring is in place and the housing are tightened if the glue lets go the O-ring can't go anywhere and the friction would not be affected. Of course this would be rubbish if it had to seal
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Post by 4l04ever on Sept 10, 2016 23:47:55 GMT 1
I don't think the O-rings form any part of the seal. Like you say, they appear to be used to stop the bearings rotating, instead of using a bearing with a locating pin.
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Post by Tobyjugs on Sept 10, 2016 23:57:05 GMT 1
Then I would not be afraid to do it
You just have to make sure you get the correct spec O- rings
If you want to know more about O-rings Google Parker O-rings it's like rocket science
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Post by russie on Sept 11, 2016 22:49:21 GMT 1
Then I would not be afraid to do it You just have to make sure you get the correct spec O- rings If you want to know more about O-rings Google Parker O-rings it's like rocket science It is rocket science, Parker Hannifin made the O-rings which failed and caused the Space Shuttle Challenger to explode! |
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Post by bare on Sept 12, 2016 4:36:09 GMT 1
erm.. Why? the perceived Need to fit O rings to the bearings either side of the Lab Seal?
IF worried about bearings spinning and you have found some Imposter Bearings that lack their requisite locking Pins?
Then it's possible /practical to use Bearing Lock to Glue the rascals in so they Won't Spin .
A fairly common and Proven technique.
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Post by steeley on Sept 12, 2016 7:40:11 GMT 1
As has been said the o ring is there to stop the bearing spinning. I have been looking into this myself for rebuilding a crank. you will find the bearings with the fixing pins/pips seem to command a high price 13 too 19 quid . you can get a bearing of the same spec with a snap ring on for half the price . also I would like to think the o ring material was resistant to modern fuel. oh while I remember you can get a kit I think Loctite do one with different size rubber cord and glue to make your own o rings .
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Post by midlifecrisisrd on Sept 12, 2016 9:21:53 GMT 1
Bin the ring and use bearing lock
Certainly not a seal, what would be the point on an open cage bearing
Steve
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Post by Tobyjugs on Sept 12, 2016 11:45:00 GMT 1
When using bearing lock glue make sure that it is the correct type
There are different types for different tolerances
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Post by steven on Sept 12, 2016 15:27:05 GMT 1
When using bearing lock glue make sure that it is the correct type There are different types for different tolerances ....and it has a shelf life. |
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Post by Tobyjugs on Sept 12, 2016 15:43:51 GMT 1
When using bearing lock glue make sure that it is the correct type There are different types for different tolerances ....and it has a shelf life. Yep thats true I have a fridge only for bier/cider and loctite ha ha |
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Post by bare on Sept 12, 2016 19:54:23 GMT 1
As has been said the o ring is there to stop the bearing spinning. I have been looking into this myself for rebuilding a crank. you will find the bearings with the fixing pins/pips seem to command a high price 13 too 19 quid . you can get a bearing of the same spec with a snap ring on for half the price . also I would like to think the o ring material was resistant to modern fuel. oh while I remember you can get a kit I think Loctite do one with different size rubber cord and glue to make your own o rings . Yesss.. OEM parts ain't Cheap.. and I am :-) But there are parts/components that only a fool would try to save a few sheckles on. Crank parts are foremost in that. |
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Post by steeley on Sept 13, 2016 7:41:55 GMT 1
If you mean save a few sheckles as in half price hmmm ,let me think about it LOL.
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